Weighted Surface Element Mapping for Lesion Displacement
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Solution Overview
Problem
Radiation therapy plans become sub-optimal due to anatomical changes, such as organ displacement and morphological changes, between the planning and treatment stages, leading to potential damage to healthy tissues and cancerous tissue extension beyond the original treatment boundaries.
Innovation Solution
A method and system for determining patient positioning corrections by generating and weighting surface elements from three-dimensional medical images taken at different times, using mapping techniques to align and adjust the patient's position to compensate for changes in lesion location and shape, incorporating certainty weights and clinical importance to ensure accurate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three-dimensional imaging modalities are used to detect and compensate for organ motion during treatment fractions, then measurement precision is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent segments the organ surface into discrete surface elements (e.g., triangles or polygons) that can be individually tracked and mapped between planning and treatment images. This segmentation allows for precise measurement of organ motion and deformation by comparing the positions and shapes of these discrete elements, thereby achieving high measurement precision without requiring overly complex imaging systems.
Solution Approach 2:
The patent transforms the complex three-dimensional organ motion problem into a series of parameter comparisons by extracting key geometric parameters (positions, orientations, shapes) of surface elements from images. By changing the representation from full three-dimensional volumetric data to discrete surface element parameters, the system achieves accurate organ motion detection while reducing computational complexity and imaging requirements.
2Manufacturing precision
If surface elements from multiple images are mapped and weighted to determine lesion displacement, then manufacturing precision is improved, but calculation complexity increases
Solution Approach 1:
The patent applies local quality by assigning different weights to different surface elements based on their reliability and clinical importance. Surface elements with higher weights contribute more to the final lesion displacement calculation, allowing the system to achieve high positioning accuracy by focusing computational resources on the most reliable and clinically relevant anatomical features rather than treating all surface elements equally.
Solution Approach 2:
The patent creates simplified two-dimensional surface element representations (copies) from three-dimensional organ surfaces. These surface element copies can be easily mapped and compared between different images without requiring complex three-dimensional registration, thereby achieving precise lesion positioning through relatively simple two-dimensional mapping algorithms.
3Manufacturing precision
If patient positioning is adjusted based on surface element mapping, then treatment precision is improved, but treatment time increases
Solution Approach 1:
The patent performs preliminary action by pre-processing the organ surface into discrete surface elements and establishing their geometric parameters during the planning stage. This preliminary segmentation and parameter extraction enable rapid comparison and mapping during treatment fractions, as the system only needs to compare pre-defined surface element parameters rather than processing full three-dimensional images in real-time, thereby achieving high positioning accuracy within limited treatment time.
Data Source
AI summary
A displacement of a lesion within a patient is determined for the purpose of administering radiation treatment by generating sets of surface elements from three-dimensional images of the lesion taken at different times. Weights are assigned to the surface elements, and based on weights and the proximity of corresponding elements in one set to elements in another set, a displacement is determined.